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tests/kernel/smp: current CPU is not atomic

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This test was whiteboxing the _current_cpu pointer to extract the CPU
ID.  That's actually racy: the thread can be preempted and migrated to
another CPU between the _current_cpu expression and the read of the ID
field.  Do it right.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
This commit is contained in:
Andy Ross 2020-02-06 12:54:17 -08:00 • committed by Anas Nashif
commit 4b670bd4f5
1 changed files with 13 additions and 3 deletions
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16
tests/kernel/smp/src/main.c
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@ -45,6 +45,16 @@ static struct k_thread tthread[THREADS_NUM];
static K_THREAD_STACK_ARRAY_DEFINE(tstack, THREADS_NUM, STACK_SIZE);
static volatile int thread_started[THREADS_NUM - 1];
static int curr_cpu(void)
{
unsigned int k = arch_irq_lock();
int ret = arch_curr_cpu()->id;
arch_irq_unlock(k);
return ret;
}
/**
* @brief Tests for SMP
* @defgroup kernel_smp_tests SMP Tests
@ -120,7 +130,7 @@ static void child_fn(void *p1, void *p2, void *p3)
ARG_UNUSED(p3);
int parent_cpu_id = POINTER_TO_INT(p1);
zassert_true(parent_cpu_id != arch_curr_cpu()->id,
zassert_true(parent_cpu_id != curr_cpu(),
"Parent isn't on other core");
sync_count++;
@ -140,7 +150,7 @@ void test_cpu_id_threads(void)
/* Make sure idle thread runs on each core */
k_sleep(K_MSEC(1000));
int parent_cpu_id = arch_curr_cpu()->id;
int parent_cpu_id = curr_cpu();
k_tid_t tid = k_thread_create(&t2, t2_stack, T2_STACK_SIZE, child_fn,
INT_TO_POINTER(parent_cpu_id), NULL,
@ -161,7 +171,7 @@ static void thread_entry(void *p1, void *p2, void *p3)
int count = 0;
tinfo[thread_num].executed = 1;
tinfo[thread_num].cpu_id = arch_curr_cpu()->id;
tinfo[thread_num].cpu_id = curr_cpu();
while (count++ < 5) {
k_busy_wait(DELAY_US);